If you have a Functor f with an instance Monoid a => Monoid (f a), f is Applicative!

liftedMonoid.hs

{-# LANGUAGE QuantifiedConstraints, ScopedTypeVariables #-}

import Data.Monoid

-- Note: fails for instances that don't need the Monoid a or Semigroup a

pureDefault :: forall f a. (Functor f, forall a. Monoid a => Monoid (f a)) => a -> f a
pureDefault a = a <$ (mempty :: f ())

apDefault :: (Functor f, forall a. Semigroup a => Semigroup (f a)) => f (a -> b) -> f a -> f b
apDefault ff fa = (\([f], [a]) -> f a) <$> fmap (\f -> ([f], [])) ff <> fmap (\a -> ([], [a])) fa